sisäelektronit
Sisäelektronit, often translated as inner-shell electrons, refer to the electrons in an atom that occupy orbitals other than the outermost valence shell. These electrons are held more tightly by the nucleus due to their closer proximity and are generally less involved in chemical bonding. The number of inner-shell electrons increases with the atomic number of an element. For example, in lighter elements, the innermost shell (n=1) is the 1s orbital, and it can hold a maximum of two electrons. As the atomic number increases, subsequent shells (n=2, n=3, etc.) also fill with electrons. These inner-shell electrons play a crucial role in determining the properties of an atom, particularly its magnetic properties and its behavior in spectroscopic analyses. While they do not directly participate in forming chemical bonds, their presence and energy levels influence the behavior of the valence electrons. The shielding effect of inner-shell electrons also reduces the effective nuclear charge experienced by the valence electrons, impacting ionization energies and atomic radii.